This invention relates to an improved process of performing reactions between at least two reactants in the presence of solid particles, i.e. catalysts present in a reaction zone, which promote the reaction.
There are many known processes of performing chemical or physical reactions between a liquid and a gas in the presence of a catalytic material. In U.S. Pat. No. 2,987,469, a process is described wherein a liquid and gas are reacted in the presence of a mass of solid catalytic particles. The catalytic particles are maintained in random motion (ebullated) within a reaction zone of a vessel by the concurrent upward flowing streams of the liquid and the gas. The ebullated mass of solid particles has a gross volume larger than that of the same mass when it is stationary. Thus, the entire reaction zone is available as a movement area throughout which each of the catalytic particles may move.
The above described process has been used, inter alia, for performing exothermic chemical reactions, such as the hydrogenation of coal or heavy hydrocarbon oils, etc., however, the process possesses certain disadvantages. Because the individual catalytic particles are in a state of random motion, the particle density of the catalytic bed in the reaction zone is relatively very low, and therefore, the charge or throughput of reactant materials through the given volume of the reaction zone must be kept relatively very low. Furthermore, because of the relatively low density of the randomly moving catalytic particles within the reaction zone, the gaseous reactant as it passes through the zone, tends to form large bubbles. These gaseous bubbles pass through the zone relatively unhindered and enter into the intended reaction to a reduced degree.
A further disadvantage of the above described process is noted when the temperature of the exothermic hydrogenation reaction is adjusted by the introduction of cold hydrogen. The introduction disturbs the flow behavior of the reactants through the catalytic bed and there is a resultant formation of a turbulent layer in the catalytic bed, which boils strongly and foams. Catalytic particles are undesirably carried out of this layer together with the reaction products.